Cab to Box pass through

Awesomeness

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I haven't seen any, though I'm confident it could be done. This topic comes up periodically, and most people seem to post saying that they think it would be too complicated to be worth doing. I think a really nice one could be designed and built, including a disconnect mechanism for when raising the cab, but it might be pretty expensive to make just one.

And it looks like that camo paintjob is the one I saw on eBay, listed as a "prepper truck" or something, with the field phone in the cab.
 

scottmandu

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I have tried several keywords in the search.. but nothing comes up. Anyone done a cab to box pass through that is flexible? I attached a couple of pictures that show the current pass through and i know this won't work as its air ride cab.. and frame flex etc..
How does one tilt the cab with a setup like that?
 

utahpow

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You have to be able to disconnect or remove the pass-through to tilt the cab @scottmandu. Take a look at the Global Expedition site. They have pass-throughs in many of theirs where they have a 1078/1088 / Brazos chassis. Like a few of these for example: http://globalxvehicles.com/safari-extreme/.

You can also post / talk to a few people on Expedition Portal (http://forum.expeditionportal.com/forums/74-Other-Custom-Expedition-Camper), but many who I've spoken with say that (1) it's a risk for water to seep in, (2) potential for more noise (3) a pass-through is "nice" but if used here in the US, who will you be running from? (4) a roof window from the RV body on back is enough for an able-bodied person to get out from this top, walk on the roof, and slide down on a ladder (if installed) to get into your truck if you need a quick getaway.

But the beautiful thing is that it's your truck :)
 

coachgeo

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Due to the high center hump in these rigs.. a crawl thru is VERY awkward and not something many folk can physically even handle. IMHO your best bet is:

Remove spare tire..... put a door on both camper box and back of cab that meet behind passenger seat. Allows for you to make it a walk thru not crawl thru. You can still use an accordion set up if you like. Putting Co-pilot and Center Pilot seats on swivels for easy access would be icing on the cake.

PS.... some type of added cab structural integrity or instead an internal or Exo cage will be needed IMHO cause door in back of Cab really reduces its overall structural integrity.. and Forward Cabs in general do not have much of that anyway.
 
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jcee

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Go to, uni-grip.com. They have various sizes and widths available. Use the term, Accordion Seals, for your search.
 

jcee

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Yea. This is a problem with accordion seals. For them to work properly both sides have to be affixed firmly to allow movement of the individual areas, cab/camper, and do what they do. If the cab side wasn't connected but was allowed to "float" when the cab is raised when you lower it back into position there'd have to be a hood or flange that would fit back over the seal. This is problematic in itself. There's no way to seal it from wind and rain because the seal is made to flex. Easy way, detach and reattach manually the cab side for raising and lowering the cab.

The other idea tossed out there was to have a door in the camper box near the cab. Open the cab door and step around to the camper door. This'll require a couple of handholds and steps to do so safely. Totally doable. In my opinion unhooking the cab side of the seal to raise the cab and then replacing it when lowered is the best setup. The seals have a tension "V" embedded in the seal to firmly hold it in place and would prevent it from falling out, becoming loose or leaking. How tight they are I don't know.

Go to the uni-grip site, shoot them an Email through the contact tab and upon request they will send you a sample.

This is a good thread. Keep it moving.
 
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jcee

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Reading back through the posts I've noticed I have forgotten one major detail which was brought to my attention by Challenger410's photo. Distance. Currently the cargo bed on an MTV is about 2' from the cab because of the spare tire, air intake, hydraulic lines, etc.. To place a box in the same location is too far for any flexible seal. Moving the box forward is the only way to make a pass through work.

As I go into this I have to admit I've yet to purchase the MV . Only because I'm flipping between an LMTV, Deuce and 5 ton. My camper plan stays the same but the truck changes. I'd prefer the LMTV because of the cab over design, rugged ability of the truck and the look. As a camper as many have found is the best of both worlds. Reason for the flip flop between MV's is one thing. The pass through. I want the security of knowing I can get to the cab in seconds without going down a ladder from the box and climbing into the cab.

So, I'm considering the Deuce or 5 ton only because of the fixed cab. On the Deuce the distance is workable with less to relocate to have the box closer to the cab and there's room in the cab to make a larger more accessible pass through. Definitely a flexible seal situation. Everything is bolted to the frame and the box could be inches from the cab not feet. The 5 ton has some of the same issues as the LMTV. Relocate the spare and other equipment.

Back to the MTV's. My plan if I decide on one is using a dry cargo box from a commercial truck or a military mobile shelter already available. The commercial box I will use has an extended bed beyond the rollup door. A perfect place for the spare. You can build the interior the way you want it. However the military shelters are insulated with an open floor plan. I'd have to raise the cab and measure as I go but it would be much less of a distance for a pass through. I'd go with a wider opening for an accordion seal, detach it when I raise the cab and press it back in place for use. Decisions, planning and lots of work. Regardless of the final plan the flexible accordion seal will be used. The finished product would be ideal.

I'm retiring in 3 months and moving from PA to Georgia next year. Once settled in this is going to happen. Lots of time for a final plan to take shape.
 

Awesomeness

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I don't think making the pass through is that difficult, it may just require a little creativity. I'm a mechanical design engineer, so thinking about stuff like this gets me excited.

1. Don't worry about the distance (2') between the cab and the box. All you have to do to solve that problem is make a fixed extension. So the box would have a 1'8" rigid tunnel that comes off it, for example, which would be braced well and sturdy. That only leaves you with a 4" (or other appropriately small but functional) gap to bridge, with your accordion seal. Add a little flip down hinged bridge inside the tunnel, that gives you a firm floor to cross that gap (it would bridge to a sturdy point in the cab, never touching the seal).

2. You can have the accordion seal attached firmly to the box tunnel and the cab, you just have to add a quick disconnect mechanism. As long as it doesn't take too much time and effort to remove, you should be fine. There are SO many ways you could approach that, my brain is going crazy just thinking about it...

- A. Something like an ammo can lid, with the center cut out like a picture frame. The tunnel/seal would pass through the picture frame. To hook/unhook it, you would flip a big latch that would release one side, then open it far enough that it can pull off/out of some mechanism that just hooks into on the other side (it could be a hinge-pin like mechanism similar to the ammo can where it slide sideways, or just a ledge that the toe of the frame hooks under, or any number of other things). This is how a lot of computer CPU retention brackets work too: http://techreport.com/r.x/system-build-howto/socketdrop.jpg

- B. More work to put on and off, but you could also just have a similar metal picture frame that pushes down on the seal with several evenly spaced quick disconnect fasteners around the perimeter. Like a big version of these sliding panel latches, for example: https://www.pegasusautoracing.com/productdetails.asp?RecID=4660

- C. You could even take off the hydraulic cylinders used to compress the suspension for shipping (because who uses those?), and use that hydraulic line to actuate a hydraulic system to compress and latch it in place. That would be super slick, because you would operate it from the knobs right there in the control box, in the same place you're about to raise the cab from following releasing the accordion seal!

As for sealing without leaking or being drafty, this seems like a simple non-issue. Just build a small flanged extension out from the cab, with a small depth of maybe 1-2". Since that flange would point outwards in all directions, your accordion seal would sit around it and create an indirect path that water and air don't flow into. You could even fill the flange gap with a buffer material (e.g. rubber, felt, etc.). You can kind of see how there is a protruding flange on the lip of this NEMA electrical enclosure, that presses into the seals in the doors: https://cdn.nexternal.com/solutionsd/images/snb-series-400.jpg

Overall, my point is that there really isn't anything about this project that poses great difficulty. At most these problems have been solved in other industries and you just have to incorporate their novel designs. It should be fun! So choose the LMTV!
 

jcee

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Great ideas! I like the hydraulic actuator to move the accordion seal in and out for a good seal. With a solid frame on it there's no way it could leak. What about applying magnetic tape to the frame to make the cab seal even better?

I like the challenge of relocating the equipment to move the box forward for another reason. You can attach a 16' box instead of 14'.

Yep the LMTV is my 1st choice because of the reasons I stated but the Deuce and 5 ton make sense also.
 
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Aernan

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Magnetic tape is far too weak. Neodymium magnets would work great. The only trouble would be prying them back off.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 

coachgeo

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Fix accordian to camper box with enough gap that when raising cab it wont scrub it off. On cab install another according that fits large around the outside of the one on the box. One that has enough depth that covers the gab... but not so deep that it scrubs itself off as you raise the cab. WHALA.... DONE (with that part). you could put a loose rubber boot that attaches with snaps orrr? to "inside" of both cab and box for final water proof. Sounds simple... but am sure it is not. Especially the "not scrub off" may be the clincher.

But that being said. I thought they made inflatable ones? Fix it to one side and inflate tight. Maybe grease up the wall on side that is NOT fixed to reduce rubbing paint off with dust that gets in there. Maybe glue a rubber sheet to the opposite wall for that reason. Again a rubber boot as described above.
 

Aernan

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To clearance the tilting cab I think the pass through should telescope or collapse.

I do like the idea of snaps. It's rugged and simple.

Ideally both the cab and box would be hard fixed so there would be no rubbing. The bellows device would need to flex.
 

utahpow

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You can move the spare tire and such sitting behind the cab to reduce the crawl-through tube length, making just a seal possible. It takes a bit of right parts and money. See an example of the space reduction on the GXV site I posted earlier or the video of Two If Overland's actual crawl-through space (fast-forward to 1 m 5 sec to see it highlighted):

https://youtu.be/WnJs2XfxTe0?t=1m5s

I'm trying to figure out the parts and placement of the gear on the back, and am hoping to meet Martin and Bethany (Two If Overland) here in SLC in the Dec time frame when they make their way back after being in Alaska.

If anyone knows the parts they are using (air cleaner, etc) and where some of these things might have been relocated, it'd be much appreciated to help me identify them. TIA
 
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coachgeo

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....
I'm trying to figure out the parts and placement of the gear on the back, and am hoping to meet Martin and Bethany (Two If Overland) here in SLC in the Dec time frame when they make their way back after being in Alaska.

If anyone knows the parts they are using (air cleaner, etc) and where some of these things might have been relocated, it'd be much appreciated to help me identify them. TIA
Air cleaner I believe is off a M939 ??
 
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